Abstract : In the domain of embedded systems, the design and the realization of performant and safety-critical real-time systems still constitute today a true scientific, technical and economical challenge [STANKOVIC88]. The difficulty is to realize, not only critical real-time systems that include more complex functions, but also to have an easier development, including verification and validation. The new solutions must be as safe as those already existing and be in accordance with the enforced standards ofthe concerned industrial domain, such as DO-178A and ARINC-653 in aerospace or CEI-880 and RFS in nuclear domain. The realization of safety-critical embedded systems with lower costs has resulted into the implementation and integration of several activities on one processor, in order to decrease the hardware costs. These systems run today correctly, but they are still expensive, difficult to maintain and do not guarantee determinism [STANKOVIC90] at the system level, therefore are inapplicable for industry. This paper begins with a presentation of the OASIS approach to mono processor architectures and presents the current research works on the distributed ones.